AusBonsai

Howdy all,
I'm trying to identify a tree, it has a dark bark, oval shaped leaves [ opposite one another on the branch ] and yellow flowers.
I'm sorry for the bad quality of the images, they were taken from my phone.









I've managed to cut two branches today :


I was hoping to make cuttings out of them, but the stems are hollow, even where the branches are coming out.
I might have taken it from a too young branch, cause the main trunk and other thicker branches are solid wood from what I can see.

Any idea what it might be anyone?

It is a Cassia, probably Cassia bicapsularis.

Thanks
Anyone ever tried to use it for bonsai use?

Im trying to see how to propagate it, but i've seen on via seeds methods so far

Yes, very tough and hardy. Will only flower on longish new growth in autumn. If you trim it after mid summer it wont flower. Also has yellow roots. It's is good to collect as old wild specimens.